1. Field of the Invention
The present invention relates to a memory control device and method for controlling a process of storing data in a memory (memory module), and a storage device using the device and method.
2. Description of the Related Art
A conventional storage device using a semiconductor memory requires management data such as an address conversion table in order to convert a logical address to a physical address.
The controller of such a conventional semiconductor memory stores the management data to a storage section of the controller and updates the data in accordance with a command from the host.
When the management data is updated in the storage section of the controller, the controller executes a writeback process in which the updated portion of the management data is written in the management region of the semiconductor memory page by page, which is the minimum writable unit.
If there is no space available in the management region of the semiconductor memory, the controller creates a new management region and stores the latest state of the management data page by page in the new management region.
An information processing device according to Patent Document 1 (Jpn. Pat. Appln. KOKAI Publication No. 6-119252) constitutes regions by using a block or several blocks as a unit. A block is an erasable unit of a non-volatile memory device. The information processing device according to Patent Document 1 erases and writes data for each region. This information processing device assigns one of the regions in the non-volatile memory device as a management information region to store the management information of the data stored in the non-volatile memory device. Each region comprises a memory areas that indicates whether it is the management information region. The management information includes a memory portion for storing the number of writings in each of the regions.
When a new management region is created, the controller of the conventional semiconductor memory stores (copies) the latest state of all the pages stored in the fully occupied management region entirely to the new management region.
For this reason, each time when a new management region is created, a certain amount of processing time is required to copy the latest state of the pages from the fully occupied management region to the new management region. This processing time increases in accordance with the number of pages.